Add profiling to mir lower and borrowck query

crates/hir-ty/src/mir/borrowck.rs

@@ -33,6 +33,7 @@ pub fn borrowck_query(
     db: &dyn HirDatabase,
     def: DefWithBodyId,
 ) -> Result<Arc<BorrowckResult>, MirLowerError> {
+    let _p = profile::span("borrowck_query");
     let body = db.mir_body(def)?;
     let r = BorrowckResult { mutability_of_locals: mutability_of_locals(&body), mir_body: body };
     Ok(Arc::new(r))

crates/hir-ty/src/mir/lower.rs

@@ -15,7 +15,7 @@ use hir_def::{
     resolver::{resolver_for_expr, ResolveValueResult, ValueNs},
     DefWithBodyId, EnumVariantId, HasModule,
 };
-use hir_expand::name;
+use hir_expand::name::Name;
 use la_arena::ArenaMap;
 
 use crate::{
@@ -1453,6 +1453,16 @@ fn cast_kind(source_ty: &Ty, target_ty: &Ty) -> Result<CastKind> {
 }
 
 pub fn mir_body_query(db: &dyn HirDatabase, def: DefWithBodyId) -> Result<Arc<MirBody>> {
+    let _p = profile::span("mir_body_query").detail(|| match def {
+        DefWithBodyId::FunctionId(it) => db.function_data(it).name.to_string(),
+        DefWithBodyId::StaticId(it) => db.static_data(it).name.clone().to_string(),
+        DefWithBodyId::ConstId(it) => {
+            db.const_data(it).name.clone().unwrap_or_else(Name::missing).to_string()
+        }
+        DefWithBodyId::VariantId(it) => {
+            db.enum_data(it.parent).variants[it.local_id].name.to_string()
+        }
+    });
     let body = db.body(def);
     let infer = db.infer(def);
     let result = lower_to_mir(db, def, &body, &infer, body.body_expr)?;

crates/hir-ty/src/mir/lower/as_place.rs

@@ -1,6 +1,7 @@
 //! MIR lowering for places
 
 use super::*;
+use hir_expand::name;
 
 macro_rules! not_supported {
     ($x: expr) => {

crates/ide-diagnostics/src/handlers/mutability_errors.rs

@@ -22,8 +22,8 @@ pub(crate) fn need_mut(ctx: &DiagnosticsContext<'_>, d: &hir::NeedMut) -> Diagno
         }
         let edit = edit_builder.finish();
         Some(vec![fix(
-            "remove_mut",
-            "Remove unnecessary `mut`",
+            "add_mut",
+            "change it to be mutable",
             SourceChange::from_text_edit(file_id, edit),
             use_range,
         )])
@@ -66,7 +66,7 @@ pub(crate) fn unused_mut(ctx: &DiagnosticsContext<'_>, d: &hir::UnusedMut) -> Di
     let ast = d.local.primary_source(ctx.sema.db).syntax_ptr();
     Diagnostic::new(
         "unused-mut",
-        "remove this `mut`",
+        "variable does not need to be mutable",
         ctx.sema.diagnostics_display_range(ast).range,
     )
     .severity(Severity::WeakWarning)